Wax-thread sewing-machine.



L. E. TOPHAM. WAX THREAD SEWING MACHINE.

APPLICATION FILED NOV. IZ, I915.

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ASSIGNMENTS, TO UNITED SHOE MACHINERY MASSACHUSE'ITS, ASSIGNOR, BY MESNE CORPORATION, 03 PATERSON,

NEW JERSEY, A CORPORATION OF NEW JERSEY.

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ilfid fiililo Application filed November 1 To all whom it may concern:

Be it known that I, LAURENCE E. Tor- HAM, a citizen of the United States, residing at Swampscott, in the county of Essex and State of Massachusetts, have invented cer tain new and useful Improvements in Waxlhread Sewing-Machines; and I do hereby declare the following to be a-full, clear, and exact description of the invention, such as will enable others skilled in the art to which. it appertains to make and usethe same.

This invention relates to wax thread sewing machines and more particularly to thread delivery controlling devices for controlling the delivery of the thread from the supply to the stitch-forming mechanism.

Qertain types of thread delivery controlling devices for wax thread sewing machines comprise a pair of thread gripping wheels or rolls between which the thread passes on its way from the supply to the stitch-torming mechanism, the rotation of one of which is controlled to control the delivery of the thread. These rolls should be relatively adjusted so that during the greater part of each cycle of operation when the thread is under comparatively a light strain they will grip the thread with sufficient force to prevent the thread lrom slipping between the rolls without crushing the thread. This requires a comparatively light pressure of the rolls upon the thread. When the take-up executes its loop-drawing stroke to set the stitch the thread between the stitch-forming mechanism and the supply is subjected to a comparatively heavy strain and a comparatively heavy pressure of the rolls on the thread is then required to prevent the thread from slipping between the rolls. Any appreciable slipping of the thread between the rolls during the stitch setting action or" the take-up results in uncertainty and lack of uniformity in the tightening of the st tches, The primary object oi the present inven-' tion is to produce a thread deliyery controlling device for'war: thread sew ng machines of the. type comprising pair of thread. gripping rolls which will control the delive of the thread in an etiicient manner without crushing the thread under the comparatively light strain exerted on the thread part of each cycle of operations and which will prevent any slipping of the thread between the rolls under Specification of Letters Eatent.

Patented Dec. er, leis.

2,1915. Serial we. cross.

the heavy strain exerted by the take-up in setting the stitch.

With this object in view a feature of the invention contemplates mounting one of the rolls for movement toward and from the other roll and the provision of means for moving the movable roll toward the other roll during the stitch setting stroke of the take-up to increase the pressure'of the rolls uponthe thread to prevent the thread from slipping between the rolls. The means for moving the movable roll toward the other roll is preferably operated by the pull or strain exerted by the take-up on the thread in setting the stitch and is constructed and arranged so thatthe harder the strain exerted on the thread by the take-up the halrder the thread will be held between the re is.

The invention is illustrated in the application as emloodied in a thread delivery controlling device in which one of the threadgripping rolls is positively rotated to cause the rolls to deliver positively the thread as required by the stitch-forming mechanism during each cycle of operations. It is to he understood, however, that, except as defined in the claims, the invention isnot limited to this particular form of thread delivery controlling device, but that it may be embodied in other forms of such devices within the scope of the claims.

The invention will be readily understood from the accompanying drawings illustrating the invention in its preferred form and the following detailed description of the structure therein shown.

ln the drawings higure tie a view in front elevation of a wax thread sewing-rna- V chine embodying the inventiong'Fig. 2 is a detail sectional view illustrating particularly the lower 'hread-gripping roll and the lever on which it is mounted; and Fig. 3 is a detail sectional view taken substantially on the line 3-3 of Fig. 2. v

The sewing machine to which the present invention is applied, as illustrated in the drawings, is a wax thread lockstitch straight hoolr needle sewing machine of the same general type as that shown and described in applicants Patent No. 1,170,022, dated Felirnary 1st, ltlld. The construction and arrangement er the needle, awl, looper, thread take-up and presser foot, and the mechanism for operating these parts is substantially the same in the present machine as in the machine illustrated in the above application. In the drawings, only the upper thread controlling mechanism has been illustrated inasmuch as this is suflicient to give livering the thread to the stitch-forming mechanism comprises a positively rotated thread roll or wheel, indicated at 12, fixed to the forward end of a shaft 14 and a loosely mounted idle wheel 16 mounted on an axis substantially parallel to the axis of rotation of the thread wheel 12 and cooperating with the thread wheel to grip the thread and draw the same from the supply, the thread passing between the rolls on its way from the supply to the work. The thread wheel 12 is formed with thread guiding side flanges 18 and with a series of teeth 20 between the flanges intermeshing with the peripheral teeth 22 formed on the idle wheel 16. The teeth on each of the wheels are constructed of less width than the recesses in the other wheel in which they engage so that the thread may be folded over the ends of the teeth and bent into the recesses between the teeth without crushing the thread. The thread as it passes on its way from the supply to the work between the thread wheel 12 and the idle wheel 16, is gripped by the intermeshing teeth of the wheels so that it is drawn from the supply by the rotary movement of the wheels.

The idle wheel 16 is held sutliciently close to the thread wheel during the greater part of each cycle of operations to enable the thread to be gripped and held from slipping against the light strain exerted on the thread in drawing it from the supply without crushing the thread. In order to enable the thread to be gripped and held securely from slipping between the thread wheel 12 and the idle wheel 16 during the stitch-setting stroke of the take-up, the idle wheel 16 is mounted for movement toward and from the thread wheel 12 and is moved toward the thread wheel 12 to increase the pressure of the wheels upon the thread as the take-up executes its loopdrawing stroke. In the construction shown the idle wheel is mounted upon the stud 24 secured at its inner end in a lever 26. The lever 26 is set into a suitably formed recess in the frame of the machine, as shown in Figs. 2 and 3, and is provided with a pivot stud 28 engaging in a bearing 30 in the frame. The stud 24 upon which the idle wheel is mounted is ofl'set from the pivot stud 30 so that the swinging movement of the lever 26 will move the idle wheel toward over the .wheel sufliciently close to the assen and from the thread wheel. The lever 26 is formed with a laterally extending arm 32 upon which is mounted a thread guideroll 34. With this construction the thread is led from the supply through the wax pot 36 over the guide roll 38, between the thread wheel 12 and the idle wheel 16, is then passed forwardly about the idle wheel and guide roll 34, and from this point extends downwardly under the guide roll 40, about the take-up roll 42, and over the guide roll 44 to the looper. Any strain or tension put upon the thread between the thread gripping wheels or rolls 12 and 16 and the work tends to swing the arm 32 of the lever 26 downwardly and to move the idle wheel 16 toward the thread wheel 12. The idle wheel 16 may be held up to the thread wheel 12 with a comparatively light pressure by the light tension exerted on the thread between the gripping wheels and the work. The face of the recess in the frame, in which the lever 26 is mounted, above the arm 32 forms a stop for the arm to limit the movement of the idle wheel 16 away from the thread wheel 12. This stop is preferably located so as to keep the idle thread wheel to prevent the thread from slipping relative to the wheels under the comparatively light strain exerted on the thread by the wheels in drawing the same from the supply. When the take-up executes its loop-drawing stroke the arm 32 of the lever 26 is swung downwardly by the heavy strain exerted by the take-up upon the thread and the movement imparted to the lever 26 lifts the idle wheel 16. This movement of the idle wheel. causes the thread to be gripped with considerable force between the opposed faces of the intermeshing teeth of the thread wheel and idle wheel so that the thread is held securely from slipping between the wheels. With this construction the greater the strain exerted by the take-up upon the thread during its loop-drawing stroke to tighten the stitch, the harder the thread will be gripped between the thread wheel and the idle wheel, so that whatever force is exerted by the take-up upon the thread, the thread will be held tightly between the thread wheel and the idle wheel against the pull of the take-up. The thread-gripping wheels therefore act as a thread lock to hold the thread securely against the stitch-setting strain of the take-up and enable the stitches to-be set in a uniform and reliable manner.

The mechanism for positively rotating the thread'wheel 12 to feed the thread as required by the stitch-forming devices may have substantially the same construction and mode of operation as the mechanism for rotating the thread wheel illustrated and described in applicants Patent No. 1,165,817, dated December .28, 1915, or any other suitgripping rolls between able mechanism may be provided for positively rotating the thread wheel.

Having explained the nature and object of the invention and having specifically described a machine embodying the same in its preferred form, what is claimed as new is 1. A wax thread sewing machine, having, in combination, stitch-forming mechanism including a take-up, athread feeding device comprising a pair of thread-gripping rolls between which the thread passes, means for positively rotating one of the rolls to feed the thread, and means for moving one of the rolls toward the other roll to hold the thread from slipping between the rolls during the stitch-setting stroke of the takeup.

2. A wax thread sewing machine, having, in combination, stitch-forming means including a take-up, a thread delivery controlling device comprising a pair of thread gripping rolls between which the thread passes, means for controlling the rotation of one of the rolls,'and means for moving one of the rolls toward the other roll to hold the thread from slipping between the rolls during the stitch-setting stroke of the takeup.

3. A wax thread sewing machine, having, in combination, stitch-forming mechanism including a take-up, a thread delivery controlling device comprising a pair of threadwhich the thread passes, means for controlling the rotation of one of the rolls, and means operated by the pull of the take-up on the thread for moving one of the rolls toward the other roll to hold the thread from slipping; betweenthe rolls during the stitch-setting stroke of the takeup.

4. A wax thread sewing machine, having, in combination, stitch-forming mechanism including a take-up, a thread delivery con trolling device comprising a pair of threadgripping rolls having intermeshing teeth between whichthe thread passes, means for controlling the rotation of one of the rolls, and means for moving one of the rolls toward the other rolls to hold the thread from slipping between the rolls during the stitchsetting stroke of the take-up.

5. A wax thread sewing machine, having, in combination, stitch-forming mechanism including a take-up, a thread feeding device comprising a pair of thread-gripping rolls having intermeshing teeth between which the thread passes, meansfor rotating one of the rolls to feed the thread, and means operated by the pull of the take-up on the thread for moving one of the rolls toward the other rolls to hold the thread from slipping between the rolls during the stitchsetting stroke of the take-up.

6. A wax thread sewing machine, having, in combination, stitch-forming mechanism, a thread delivery controlling device comprising a pair of thread-gripping rolls between which the thread passes, means for controlling the rotation of one of the rolls, and means for varying the pressure of the rolls upon the thread during each cycle of operation. i 7. A wax thread sewing machine, having, in combination, stitch-forming mechanism, athread deliver Ey controlling device com prising a pair 0 thread-gripping rolls between which thethread asses, means for controlling the rotation 0? one of the rolls, and means controlled by the strain upon the thread for varying the pressure of the rolls on the thread.

8. A sewing machine having, in combination, stitch forming mechanism, a thread delivery controlling device comprising a thread engaging roll member, means for controlling the rotation of the roll member, a second thread engaging member arranged to cooperate with the roll member to grip the thread,- and means for imparting a movement of translation to one of said members to increase the force with which the thread is gripped by the roll member at a certain period in each cycle of operations.

. LAURENCE E. TOP. 

